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From:   Allen Webb <allenwebb@google.com>
Date:   Tue, 20 Dec 2022 12:19:49 -0600
Message-ID: <CAJzde04igO0LJ46Hsbcm-hJBFtPdqJC6svaoMkb3WBG0e1fGBw@mail.gmail.com>
Subject: Re: [PATCH v9 02/10] rockchip-mailbox: Fix typo
To:     Luis Chamberlain <mcgrof@kernel.org>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "linux-modules@vger.kernel.org" <linux-modules@vger.kernel.org>,
        "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>, stable@vger.kernel.org,
        kernel test robot <lkp@intel.com>
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On Tue, Dec 20, 2022 at 12:12 PM Luis Chamberlain <mcgrof@kernel.org> wrote:
>
> On Tue, Dec 20, 2022 at 08:58:36AM -0600, Allen Webb wrote:
> > As mentioned in a different sub-thread this cannot be built as a
> > module so I updated the commit message to:
> >
> > imx: Fix typo
> >
> > A one character difference in the name supplied to MODULE_DEVICE_TABLE
> > breaks compilation for SOC_IMX8M after built-in modules can generate
> > match-id based module aliases, so fix the typo.
>
> Are you saying that it is a typo *now* only, and fixing it does not fix
> compilation now, but that fixing the typo will fix a future compilation
> issue once your patches get merged for built-in module aliases?

It was always a typo, it just doesn't affect the build because
MODULE_DEVICE_TABLE is not doing anything for built-in modules before
this patch series.

>
> > This was not caught earlier because SOC_IMX8M can not be built as a
> > module and MODULE_DEVICE_TABLE is a no-op for built-in modules.
>
> Odd, so why did it use MODULE_DEVICE_TABLE then? What was the reason for
> the driver having MODULE_DEVICE_TABLE if it was a no-op?

That is a good question. I can only speculate as to the answer but it
is plausible people copied a common pattern and since no breakage was
noticed left it as is.

It also raises the question how many modules have device tables, but
do not call MODULE_DEVICE_TABLE since they are only ever built-in.
Maybe there should be some build time enforcement mechanism to make
sure that these are consistent.

>
>   Luis